1. Field of the Invention
This invention relates to a spreading device for stacks of laminations of electric machines, in which a spreading mandrel, which can be axially displaced by a hydraulic drive, receives sector pieces which fit into the hole of the lamination stack. The sector pieces have beveled faces on their inside edges which rest against a first conical surface connected to the spreading mandrel and a movable second conical surface facing the first one.
2. Description of the Prior Art
In one, existing, spreading device the second conical surface is stationary. In this structure, the danger exists that the sector pieces will not slide on this stationary conical surface by the same amount as they will on the conical surface which moves axially with the spreading mandrel. This results in a non-uniform alignment of the lamination stack. In addition, the sector pieces are displaced, in this spreading device, in the axial direction of the spreading mandrel. In order to avoid axial motion between the sector pieces and the lamination stack, the lamination stack must be supported by an axially movable support.
It is an object of the invention to provide a spreading device which operates so that the lamination stack is aligned uniformly over its entire length and there is no axial motion of the lamination stack.